Press freedom group Reporters Without Borders (RSF) has announced it will become a joint plaintiff in a complaint filed by French newspaper Le Monde, which accuses government officials of violating new legislation intended to protect the secrecy of journalists’ sources.

Le Monde claims that an intelligence service was used by the French President’s office to identify a source used in a story on L’Oreal heiress Liliane Bettencourt and donations made to President Sarkozy’s 2007 election campaign.